FAQs About UI Parallelization

How to Obtain and Use Multi-thread NDK APIs

From API version 22, ARKUI_MULTI_THREAD_NATIVE_NODE is added to ArkUI_NativeAPIVariantKind.

Call the OH_ArkUI_GetModuleInterface API and pass ARKUI_MULTI_THREAD_NATIVE_NODE as the input parameter to obtain the multi-threaded NDK API set. Refer to Using Multi-threaded NDK APIs for the complete example.

Calling a multi-threaded NDK API returns the ARKUI_ERROR_CODE_NODE_ON_INVALID_THREAD error code.

Problem

Calling a multi-threaded NDK API returns the ARKUI_ERROR_CODE_NODE_ON_INVALID_THREAD error code.

Solution

Refer to Multi-threaded NDK API Set Specifications to check whether the called API supports multi-thread calling, and then perform the following steps:

1. If the API can be called only on the UI thread, adjust the function call timing and call the API on the UI thread.
2. If the API supports multi-thread calling, the error occurs because the node operated by the API is in the Attached state.
   • Check whether the node is created by the multi-threaded createNode API.
   • Remove all non-convertible attached components from the component tree where the component is located by referring to Multi-threaded NDK API Set Specifications.

How to Ensure Thread Safety When Operating ArkUI Components in Multiple Threads

When multi-threaded NDK APIs are used, multiple threads operate the same component or component tree at the same time. In this case, thread safety cannot be ensured. You need to avoid this situation through proper architectural design.

You can follow the restrictions in Multi-threaded NDK API Set Specifications to ensure thread safety.